Demonstrating the impact of professional learning has never been more important. Educators are implementing rigorous content standards and assessments and experiencing new evaluation systems, even as they navigate a sea of other challenges and resources for professional learning are on the chopping block. For educators to be successful in ensuring that students are college- and career-ready, the support school systems provide must include high-quality professional learning. But without indications that professional learning has an impact, why would school systems continue to invest in it? And how can educators stay committed to lifelong learning that requires their own investment of time and energy if they don’t see an impact on what they do each day? Agreement among decision makers and advocates about professional learning’s purpose and